A gene or transcription unit consists of that portion of the DNA extending from the promoter site to the termination site. The positions and sequence content of eucaryotic and viral promoter elements as well as the start sites of RNA polymerase II transcription have been well characterized in recent years. In contrast, the RNA polymerase II termination sites in eucaryotic transcription units have received much less study. A major objective of the proposed research is to identify eucaryotic RNA polymerase II termination regions in transcription units, to understand the process of mRNA 3'-end formation, and to assess the validity of the hypothesis that transcription termination may have a regulatory role in eucaryotic gene expression. The specific aims of this research are to search for transcription termination sites within the adenovirus 2 genome and to study the interactions of adenovirus 2 with nonpermissive host cells to determine the role of viral and cellular control elements in the regulation of viral RNA transcription. Transcription termination sites for adenovirus 2 early genes will be identified by RNA nascent chain analysis. Nascent unprocessed RNA, labeled in both infected whole cells and in isolated nuclei, will be analyzed by hybridization to a library of different M13 single-stranded recombinants containing appropriate adenovirus 2 DNA inserts. To gain insight into the regulation of viral RNA transcription, adenovirus 2 transcription will be characterized in HeLa cells at different times after infection and in nonpermissive rodents cells. The significance of this work rest in the anticipation that gene expression in uninfected eucaryotic cells is regulated similarly to that of adenovirus, and hence what is learned about adenovirus gene regulation will further our understanding of the expression of cellular genes in normal and in malignant cells.